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Wipe - Mask or No Mask

Posted: Fri Sep 30, 2022 3:22 am
by Startrek
I’ve been using ST for 6 years now and have never used a Mask with Wipe
I understand that Wipe will back off in the un sampled area ( usually the main object ) and concentrate on the masked area or background to mitigate LP and dust donuts and other anomalies and provide an even clean field
I always use calibration frames with my imaging

What happens when your image is all detailed structures and nebulosity across the whole frame , where would you apply a mask in Wipe ?

Comments / expertise most welcome

Clear Skies
Martin

Re: Wipe - Mask or No Mask

Posted: Fri Sep 30, 2022 6:04 am
by admin
Startrek wrote: Fri Sep 30, 2022 3:22 am I’ve been using ST for 6 years now and have never used a Mask with Wipe
I understand that Wipe will back off in the un sampled area ( usually the main object ) and concentrate on the masked area or background to mitigate LP and dust donuts and other anomalies and provide an even clean field
I always use calibration frames with my imaging

What happens when your image is all detailed structures and nebulosity across the whole frame , where would you apply a mask in Wipe ?

Comments / expertise most welcome

Clear Skies
Martin
Hi Martin,

These days, you're usually fine just letting Wipe do its thing, even if your entire dataset contains nebulosity. Nebulosity, particularly in mid-to-widefields is "busy" enough for Wipe to totally disregard it (and thus preserve it).

Also, if you're sure you don't have any sort of gradient going on in your image, then you can use the NarrowBand preset settings. This will just look for a single (most conservative) background value that is true for the entire dataset and just subtract that, without looking for any further undulation in your dataset.

Masks are usually only necessary in the cases you already highlighted; sudden dips in the background's brightness due to non-celestial "detail", such as dust donuts/specks, clustered dead pixels, or any other sorts of dark anomalies.

Does that help?

Re: Wipe - Mask or No Mask

Posted: Fri Sep 30, 2022 6:31 am
by Startrek
Hi Ivo,
Perfectly understood
Thanks
Maybe an amendment in the User Notes for Wipe regarding not having to use a Mask ?
The User Notes seem as if you have to use one for every image especially when it comes to a first time user of ST
Just a thought ?
Clear Skies
Martin